[ntp:questions] Red Hat vote for chrony

David Woolley david at ex.djwhome.demon.invalid
Tue Dec 9 08:08:43 UTC 2014

On 09/12/14 07:06, Charles Swiger wrote:
> Yes, I also find it a bit surprising than modern desktop CPUs and GPUs
> are willing to run right up to their thermal trip points of ~80 C or so
> rather than bump up fan speed a little more to keep them more around 50 C.

Cost engineering, for what is a throwaway product with a fashion life of 
less than 3 years.  Also,
> Older systems tended to use more aggressive cooling, especially laptops.
> Well, smarter firmware and Hall effect sensors to measure fan speed means
> you can spin the fans more slowly than if you needed to apply 40% minimum
> speed just to be sure that the fan would spin up from idle.

Variable speed fans are available now and motherboards support them. 
Tachometer outputs have been around for a long time, and because fans 
use brushless "DC" motors (i.e. synchronous motors with electronics to 
generate the AC) they all have to have rotational phase detectors 
(although it may be done by monitoring the coil current, rather than a 
separate sensor).  Heavy use of these tends to be associated with "quiet 
PCs", so the BIOS may well be set for minimal cooling, rather than 
keeping a low temperature.

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